Quantum physics has just taken a hot stroke (and it’s a revolution)

For decades, scientists have believed that quantum phenomena – these quirks of physics where a particle can be in several states at the same time – could only exist in extremely cold conditions, close to absolute zero. But a team of researchers has just shaken up this certainty by succeeding in recreating a state of cat from Schrödinger … at a surprisingly “hot” temperature according to the standards of quantum physics. A technical feat that opens the way to a revolution in quantum technologies, so far limited to cryogenic environments.

Schrödinger’s cat … “hot” version

To fully understand what makes this discovery so spectacular, a little reminder is essential. In 1935, the Austrian physicist Erwin Schrödinger proposed an experience of thought that has become famous for illustrating the quantum worlds. He imagines a cat locked in a box, alongside a device linked to a subatomic particle. If this particle disintegrates, a poison is released and the cat dies. If it does not disintegrate, the cat remains alive.

But as long as the box remains closed and no one looks inside, the cat is both alive and dead. This strange state, called quantum superposition, means that a system can exist in several states at the same time – until an observation comes to “freeze” reality in a single state.

Today, this paradox is no longer just an abstract idea. Scientists manage to recreate laboratory superposition states, symbolically calling them “cat states”. The problem ? These states are extremely sensitive. The slightest external disturbance – and especially the heat – is in fact to make them collapse. Indeed, heat causes random movements in atoms, called thermal noisewhich disturb quantum states, as a vibration in a card castle.

This is why, so far, quantum experiences required ultra-low temperatures, close to absolute zero (−273,15 ° C), in order to limit this noise and protect these fragile states. This major technical constraint made quantum technologies that were difficult to use outside the laboratories.

However, it is precisely this barrier that researchers from the University of Innsbruck have just crossed. In a study published in Science Advancesthey announce that they have managed to create a Schrödinger cat at 1.8 Kelvin, about −271.3 ° C. It remains freezing for us, but in quantum physics, it’s almost tropical.

How did they succeed in this feat?

To achieve this in -force, the team of researchers used a transmonious qubit, a type of quantum circuit based on a superconductive material. This qubit was placed inside a superconductive microwave resonator, in other words a kind of “box” capable of trapping and storing microwave energy without practically no loss. This ultra-precise system makes it possible to control quantum states with finesse.

But that’s not all: the researchers used two particularly ingenious protocols to manipulate these fragile states. The first, called ECD (conditional displacement with Echo), is to move a quantum state in a certain direction, then apply an “echo” to correct any errors. It’s a bit like adjusting the trajectory of an airplane in flight: you guide it, then stabilize it.

The second protocol, QCMAP (quantum control mapping) is based on the tangle of two quantum elements. By making them interact, it becomes possible to control the state of one by manipulating the other, a bit as if two puppets were connected by invisible wires. Together, these two methods make it possible to create and maintain quantum superposition states, even when the environment is warmer than what was believed to be possible.

In other words, the team has shown that Schrödinger’s famous cat could survive in much less extreme conditions, breaking a major dogma of quantum physics.

What does it mean?

Until now, one of the largest brakes on the development of quantum technologies-such as quantum computers-was the need to maintain ultra-low temperatures, which makes heavy, expensive and difficult to deploy systems outside specialized laboratories.

But this new discovery proves that quantum effects can survive less extreme conditions. This means that in the future, we could see more robust quantum technologies emerge, more accessible and adapted to real contexts – outside the refrigerated laboratories.

Towards a more realistic quantum future?

This discovery is not an end in itself, but rather an opening. By showing that it is possible to create a state of Schrödinger cat at a temperature other than icy, the researchers open the way to new quantum devices operating under more flexible conditions. This could speed up the arrival of quantum commercial computers or ultra-preccosed quantum sensors in our daily lives.

And who knows? Maybe tomorrow Schrödinger’s cats will be able to get out of their box and purr in less extreme conditions. What seemed until then reserved for delicate and esoteric experiences is gradually becoming tangible, realistic and promising.